Torsion bar construction



y 19359 J. KALES EIAL 2,893,724

TORSION BAR CONSTRUCTION Filed Oct. 26. 1955 I z.

u M Ma 1M. k P E m DIPL.-IAIG. ALBEKT cmzz'wouL BY j 5 MITH, 01 suv'd K0m A TTORNEYS United States Patent TORSION BAR CONSTRUCTION Josef Kalesand 'Albert Grotewohl, Wolfsburg, Niedersachsen, Germany, assignors toVolkswagenwerh G.m.b.H., Wolfsburg, Germany Application October 26,1955, Serial No. 542,982 1 Claim. (Cl. 267-57) This invention concernstorsion bars.

When a group of spring torsion bars consisting of layered spring leavesis twisted, the outer leaves also require bending in addition totwisting. If in this case all the leaves, as is cutomary, are of equalwidth and are arranged in a receiving member of rectangularcrosssection, the outer leaves additionally experience strong localcompressions due to the setting up of the twisting moment in the fixedend. Fractures which occur therefore begin exclusively from the point ofsupport of the outer leaves. The loading capacity of the whole group isconsequently limited by the danger of overloading the outer leaves atthe fixed end, while the inner layers are not fully utilized.

According to the present invention, in a torsion bar assembly consistingof layered spring leaves, particularly for mechanically propelledvehicles, the leaves superimposed upon one another are of varying width,decreasing from the centre of the assembly outwards in such a way thatsaid assembly is adapted to be received in a bush of circularcross-section.

By means of the varying width of the leaves, an approximately uniformutilization of every individual rectangular bar can be achieved. Bearingin mind that in all the bars the individual maximum loads are to be asfar as possible approximately equal to one another, it may be foundconvenient also to vary the thickness of the bars in addition to varyingtheir widths. The most favorable dimensioning of the individualthicknesses will be calculated for each specific case. In general, avariation of thickness decreasing from the inner to the outer bars willbe the one employed, although other arrangements are also possible, e.g.that in which the innermost bars are made the thickest, the outermostbars less thick, and the intermediate bars the thinnest.

The possibility also exists of so dimensioning the outermost bars inwidth and/or thickness that they are loaded to a somewhat lesser degreethan the remaining bars situated between them. A fracture then possiblyoccurring would thus in all likelihood appear only on one of theintermediate bars. The advantage as compared with a group of bars of thesame thickness and width throughout, with fractures taking place only inthe outside leaves, is that the effective volume of the spring assemblyis scarcely reduced, since a broken intermediate leaf is almostcompletely turned jointly by the two neighboring leaves.

A further advantage of the invention is that, compared with a group ofbars of equal width, it gives a better utilization of the circumscribedcircle, and thus a receiving member of smaller size may be employed,and, in the case of a mechanically propelled vehicle, a lightersupporting arm. If the receiving member is also toothed internally, thenin place of a concentration of the local compressions resulting from thetwisting moment in the two outside bars, a distribution of the pressuresover several or all of the bars takes place.

The invention will be described further, by way of example, withreference to the accompanying drawings, in which:

Fig. l is an end elevation of a group of spring bars constructed inaccordance with the invention, and

Fig. 2 is an end elevation, partly in section, of a torsion bar andsupporting arm assembly constructed in accordance with the invention.

The torsion bar assembly shown in Fig. 1 consists of eight single bars 1of diflierent width and thickness from one another, and presenting atotal cross-section which almost completely occupies the imaginarycircumscribed circle 2.

In the embodiment shown in Fig. 2, a supporting arm 3 is formed at oneend with an internal toothed bore 6. Bore 6 provides teeth 7 whichreceive a torsion bar assembly comprising nine bars or leaves 1 varyingboth in thickness (in the arrow 8 direction) and in width (in the arrow9 direction). It will be noted that the torsion bar assembly is ofgenerally stepped configuration so as to expose the lateral areas ofindividual bars, the arrangement being such that the teeth formed by bar6 engage said lateral areas of the leaves to rigidly anchor the leverarm 3 and individual ones of the leaves together. The bars 1 areretained in the supporting area 3 against axial displacement by means ofa screw 4 and locknut 5.

We claim:

A torsion bar assembly comprising a plurality of flat layered springleaves; adjacent ones of said leaves varying substantially in width fromone another, with the leaf width decreasing from the center of theassembly outwardly to provide a stepped configuration; a lever armhaving a bore conforming to the stepped configuration of the springleaves and engaging the exposed lateral areas of the flat leaf surfacesto rigidly anchor the lever arm and adjacent portions of the springleaves together; the individual leaves being of dilferent thickness,decreasing generally from the inner to the outer leaves.

References Cited in the file of this patent UNITED STATES PATENTS2,194,964 Willson Mar. 26, 1940 2,778,626 Klepp Jan. 22, 1957 FOREIGNPATENTS 20,027 Austria May 10, 1905 146,568 Great Britain June 18, 1920632,998 Great Britain Dec. 5, 1949 962,3 82 France Dec. 12, 1949

